1 files changed, 93 insertions, 0 deletions
diff --git a/libc/arch-riscv64/string/strnlen_vext.S b/libc/arch-riscv64/string/strnlen_vext.S
new file mode 100644
index 000000000..f546689bb
--- /dev/null
+++ b/libc/arch-riscv64/string/strnlen_vext.S
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Copyright (c) 2023 SiFive, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the company may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY SIFIVE INC ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL SIFIVE INC BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if defined(__riscv_v)
+
+#include "sys/asm.h"
+
+#define pStr a0
+#define pCopyStr a2
+#define iRetValue a0
+#define iMaxlen a1
+#define iCurrentVL a3
+#define iEndOffset a4
+
+#define ELEM_LMUL_SETTING m1
+#define vStr v0
+#define vMaskEnd v8
+
+ENTRY(strnlen_vext)
+
+    mv pCopyStr, pStr
+    mv iRetValue, iMaxlen
+L(strnlen_loop):
+    beqz iMaxlen, L(end_strnlen_loop)
+    vsetvli zero, iMaxlen, e8, ELEM_LMUL_SETTING, ta, ma
+    vle8ff.v vStr, (pCopyStr)
+    vmseq.vi vMaskEnd, vStr, 0
+    vfirst.m iEndOffset, vMaskEnd /* first occurrence of \0 */
+    csrr iCurrentVL, vl
+    add pCopyStr, pCopyStr, iCurrentVL
+    sub iMaxlen, iMaxlen, iCurrentVL
+    bltz iEndOffset, L(strnlen_loop)
+    add iMaxlen, iMaxlen, iCurrentVL
+    sub iRetValue, iRetValue, iMaxlen
+    add iRetValue, iRetValue, iEndOffset
+L(end_strnlen_loop):
+    ret
+
+END(strnlen_vext)
+
+#endif